Scientists discovered that cooling effect caused volcanic eruptions Earth’s surface temperature is probably underestimated by twice, perhaps even four times.in the usual weather forecasts.
although this is true far from being sufficient to offset the effects of rising global temperatures. Researchers led by the University of Cambridge (England) have found that human activity causes Small eruptions are responsible for more than half of all sulfur gases emitted. into the upper atmosphere by volcanoes. These gases help cool the air.
The results were published in the journal Geophysical Research LettersHe suggests that improving knowledge about volcanic eruptions of all sizes will make climate projections more robust.
Where and when a volcano erupts is not something humans can control, but eruptions play an important role in the global climate system. When volcanoes erupt, they can spew sulfur gases into the upper atmosphere and tiny particles called aerosols that reflect sunlight back into space. In very large eruptions like the one at Mount Pinatubo in 1991, the volume of volcanic aerosols is so large that it alone causes global temperatures to drop.
However, these major eruptions occur only a few times per century; Most small eruptions occur every one to two years.
“Compared to the greenhouse gases emitted by human activities, the impact of volcanoes on the global climate is relatively small.but it’s important that we incorporate them into climate models to accurately assess future temperature changes,” said first author May Chim.
The effect of small explosions
Standard climate projections, such as the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report, assume that explosive volcanic activity between 2015 and 2100 will be at the same level as 1850-2014, but They overlook the effects of small explosions.
“These estimates rely primarily on ice cores to predict how volcanoes might affect climate, but smaller eruptions are too small to be detected in ice core records,” Chim said. “We wanted to make better use of satellite data to fill that gap and account for eruptions of all sizes.”
Using the latest satellite and ice core records, Chim and colleagues from the University of Exeter and other European scholars have produced 1,000 different scenarios for future volcanic activity. These assumptions recreate low, medium, and high levels of volcanic activity. They then ran climate simulations using the UK Earth System Model.
Their simulations showed that the impact of volcanic eruptions on the climate, including global surface temperature, sea level and sea ice coverage, was underestimated because current climate projections greatly underestimate the estimated level of volcanic activity.
For the mid-future scenario, they found: The impact of volcanoes on the atmosphere, known as volcanic forcing, is underestimated by up to 50% in climate projections.largely due to the impact of small-sized explosions.
“We found that not only is volcanic forcing underestimated, but small-sized eruptions are actually responsible for more than half of all volcanic forcing,” Chim said. Said. “These small-sized explosions may not have a measurable impact individually, but collectively their impact is significant.”
“I was surprised to see how significant these small-sized explosions were: We knew they had implications, but we didn’t know they were this big,” he added.
They do not offset CO2 emissions by humans
Although climate estimates underestimate the cooling effect of volcanoes, the researchers stress that these cannot be compared to human-induced carbon emissions.
“While volcanic aerosols in the upper atmosphere usually remain in the atmosphere for one to two years, carbon dioxide stays in the atmosphere much longerChim said.
“Even if we had an extraordinarily high period of volcanic activity, our simulations show that this will not be enough to stop global warming. It’s like a passing cloud on a hot, sunny day: the cooling effect is only temporary.‘, he explained.
Fully accounting for the impact of volcanoes could help make climate projections more robust, the researchers say. They are now using their simulations to investigate whether future volcanic activity will threaten the recovery of the Antarctic ozone hole, as a result of which they retain relatively high levels of harmful ultraviolet radiation on the Earth’s surface.
Reference work: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2023GL103743
……….
Contact details of the environment department: [email protected]